Installing vSphere VI Client on Server 2012 Fails – Error 28173

Problem

If you attempt to install the VI client, (in this case on a 2012 R2 Datacenter Server), you may see this error;

Error 28173. Setup failed to enable Microsoft .NET Framework 3.5 Refer to Microsoft KB article 2734782 and 3002547 which may help you resolve the .NET failure. You will need to enable this feature in Windows Server Manager before installing vSphere Client.